As a recently established TTI at the NCI, only very preliminary results in this project can be presented: -Using published data from RNAseq analysis from single cells at different stages of embryonic development we detected a very timely and exquisite regulation in the expression of ETS-transcription factors. These TFs are candidates that we will study to determine their role during development. During FY2019 we have been setting up different mouse embryonic stem cell lines (mESCs) to induce the expression of several of these ETS factors. These cell lines will be used to study gene expression by RNAseq and chromatin binding landscape by ChiPseq. -We further investigated the role of the ETS factor ERF in cell fate using 3D models of cell commitment in mESCs. Finally, we are extending our experiments to investigate the role of another repressor, Capicua (CIC), regulating cell fate in mESCs. Together, we expect to validate our hypothesis of existing transcriptional repressors preventing aberrant commitment in the absence of the appropriate signaling context.